Polycom 400 - Manual (Page 106)

Polycom Telephone User Guide Set Up Outlook for TAPI 99
621-00000092
6. Choose where to save the TAPI.EXE file and click Save. This
example saves it to the desktop to be easy to find.
7. Find the TAPI.EXE file (shown here on the PC desktop) and
double click it to run the install program.